NAIMA is a non-profit certification program for technicians in the heating, ventilation, air-conditioning, and refrigeration (HVACR) industry and the only test supported by the entire industry.

North Shore Heating & Cooling, is an Illinois (IL) Heating, Cooling, Air Conditioning, Water Heater, Boiler, and Furnace repair, service, replacement and maintenance company, located in Glenview area. North Shore Heating & Cooling employs only the best technician for air conditioner repair, furnace repair, and water heater repair as well as all air conditioner replacement, furnace replacement, and boiler replacements.

Established in 1927, North Town Home Services provide expert appliance repair service, as well as repair and replacement services. From their highly skilled technicians to their professional sales and support staff, it is their hope that you will be absolutely satisfied with this one-of-a-kind, world-class experience.

Northeast Technical Institute prepares people throughout Maine with new and marketable trade skills, allowing them easy access to exciting careers. Their real-world training equips with the job skills and national certification that the employers are seeking. They provide HVAC training, technical school, vocational school, commercial driving, and certifications.

Northern Air Mechanical offers air conditioning repairs, installs, ventilation, refrigeration, ductwork, and all other HVAC installation/repair services - both commercial and residential - to homeowners and businesses across the East Valley including San Tan Valley, Queen Creek, Mesa, Chandler, Gold Canyon, and Apache Junction.

Northern Weathermakers HVAC, Inc. provides a range of solutions, including in the scope of Building Automation, Equipment Replacement, Preventative Maintenance and HVAC solutions.

Based out of Minnesota, USA, Northern's One Hour Heating & Air Conditioning provides solutions like Air Conditioning, Heating, Furnaces, Air Quality and other HVAC services.

Northland Heating are HVAC contractors that provide service and repair for heating, air conditioning, boiler, and furnace systems. They also conduct sheet metal work, including ductwork, remodels, new houses, and more.

Northrop Grumman is a global security company providing innovative systems, products and solutions in unmanned systems, cyber, C4ISR, and logistics and modernization to government and commercial customers worldwide.

NovaFlex manufactures flexible ducting, hoses, extruded thermo-plastic ducts, adapters, PVC pipping, water and steam heaters, couplers and adapters. Designed for superior flexibility, for material handling, woodworking, welding exhaust, high temp., custom OEM applications and more.

NovelAire provides innovative indoor air quality solutions to Original Equipment Manufacturers (OEMs) serving the residential, commercial and industrial markets of the Heating, Ventilation and Air Conditioning industry. Serving hundreds of OEM accounts worldwide, NovelAire has attained a reputation for innovation, flexibility, and superior product quality and customer service.

NOW Specialties, Inc. is the exterior wall system designer, fabricator, and installer in Texas. NOW was the first ACM fabricator, and is still the only MCA Premium Fabricator in Texas. They provide fabrication solutions for the installation of barrier systems, rainscreen systems, louvers and much more.

NPM Heating & Cooling, LLC provides a wide range of heating, cooling and air quality solutions, which include AC installation and servicing, furnace repair, replacement and tune up, and home air quality solutions.

NSG Heating and Air Specialists, LLC stands as a beacon of relief for those enduring the soaring temperatures in Fort Worth, TX. Specializing in all facets of Fort Worth air conditioning repair – from installations fine-tuned for optimal airflow to thoroughgoing repairs – they aim to keep their living or work area at the perfect temperature all year round.

NTT Training is about delivering very practical hands-on safety and trade skills to workers around the world. They deliver the most comprehensive, skills-based HVAC training programs and Hands-On Training.

Nu-Mun Contracting is a Calgary based plumbing company formed by Doug Muncaster in 1989. They provide sheet metal installations for commercial, industrial and residential applications. The company also offers air conditioning, residential plumbing, commercial plumbing, and other HVAC solutions.

nVent RAYCHEM is a provider of heat-trace management systems for infrastructure, industrial, commercial and residential buildings, with operations globally. They help customers enhance productivity and reduce their costs by simplifying installation and minimize downtime during operation.

O.T. Hall & Son has been successfully promoting electrical, lighting, heating and networking products since 1920. They are family-owned and operated and service Maryland, DC, Virginia, Delaware and the panhandle of West Virginia.

Oahu Air Conditioning Service (OACS) provides the highest quality air conditioning service to commercial customers of all sizes. They provide preventative maintenance and repair services to office buildings, hotels, condominium associations, banks, shopping centers, airports, hospitals, and various state and government buildings throughout Hawaii.

Oak Grove Heating & Air Conditioning they supply reliable HVAC systems and quality work in Hattiesburg. Their techs are knowledgeable in a wide range of services, so one can be confident in the outcome they have.

Oakes Energy Services Ltd (Oakes Energy) designs and installs both commercial and domestic renewable energy systems. In turn, dramatically reducing the cost of energy consumption and enabling the business or home to save thousands of pounds on their energy bills. Oakes Energy Services Limited was established in 2007 with the aim of offering customers an alternative, more sustainable approach to their energy needs.

Oakley Transport is dedicated to transporting liquid food grade products in the contiguous United States and also Canada and Mexico. They are pioneers in the liquid bulk food grade transportation industry for quality service at a price sensitive value.

Oakwood Homes, a Berkshire Hathaway company, has always built, sourced and stayed true to what's local. By leveraging resources and partners right here at home, they can deliver true luxury in homes at every price point - for people in every stage of life.

With the Occupational Safety and Health Act of 1970, Congress created the Occupational Safety and Health Administration (OSHA) to ensure safe and healthful working conditions for workers by setting and enforcing standards and by providing training, outreach, education and assistance. The OSH Act covers most private sector employers and their workers, in addition to some public sector employers and workers in the 50 states and certain territories.

Oceanair (Oceanair UK Ltd.) is an award-winning distributor of air conditioning and heating products. They use their wealth of industry experience to help consultants, installers and end-users achieve their objectives by developing cost effective, energy efficient solutions they trust us to deliver. They offer a complete design service for both Air to Water (A2W) and Air to Air heat pumps.

OceanAire is a manufacturer of portable air conditioning units, built specifically for commercial and industrial use. They provide portable air conditioners and heat pumps. 1-5 ton air-cooled and water-cooled models.

OEI is a second generation, family-owned and operated business offering air conditioning and heating services to home or business. Rely on their certified technicians for advice, sales, repairs, and installations.

Official Heating & Cooling providing residential home comfort services to Chicago's North and Northwest Suburbs.

Ofgem is Britain’s independent energy regulator. Their role is to protect consumers now and in the future by working to deliver a greener, fairer energy system. They are a non-ministerial government department and an independent National Regulatory Authority.

For more than half a century, OJ Electronics have been designing and developing electronic controls for electric underfloor heating and HVAC Controls & Drives. They give access to deep application knowledge and innovative power and help differentiate themselves in the market. They are here to help build their customers’ business.